Backup tong for power pipe tongs



A ril 21, 1970 J. DICKMANN BACKUP TONG FOR POWER PIPE TONGS 5Sheets-Sheet 2 Filed Dec. 4, 1967 wsm mfiw mum mum mm NNN QQQ QQNINVENTOR JOHN 4' D/CKMAA/A/ BY g J/A ArmeA/a A ril 21, 1970 J. DlCKMANNBACKUP TONG FOR POWER PIPE TONGS 5 Sheets-Sheet Filed Dec. 4, 1967 WW mM 0 EM 7 z r m A 0 v WM w&

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J. L. DICKMANN BACKUP TONG'FOR POWER PIPE TONGS 5 Sheets-Sheet 5 UnitedStates Patent US. Cl. 8157.18 13 Claims ABSTRACT OF THE DISCLOSURE Abackup tong for power well pipe tongs including pipe gripping jawspositively operable to grip pipe therebetween and positively retractablein response to rotation of a jaw carrying ring relative to a supportingstructure, the supporting structure being supportable beneath apower-operated tong adapted to make up and break out pipe joints, onejoint part of which may be gripped in the back-up tong, and a hydrauliccylinder being connected selectively to angularly spaced locations onthe jaw carrying ring from a remote control point to enable actuation ofthe jaw carrying ring in opposite directions relative to the supportstructure.

Background of the invention The present invention relates to pipe tongs,and more particularly to a pipe-gripping backup tong adapted to beemployed in combination with a power driven tong, so that the parts of ajoint of well pipe may be made up or broken out, the pipe-gripping meansof the backup tong having application as well to other pipe tongs.

In the operation of power pipe tongs to make up and break out joints inwell pipe, such as drill pipe, casing or tubing, all herein generallyreferred to as pipe, it is necessary that the length of pipe disposed inthe well bore be held stationary during rotation of the length of pipesuspended in the derrick. While the length of pipe suspended in thederrick or the length of pipe disposed in the well bore may be rotatedrapidly during the initial stages of making up the joint or in thelatter stages of breaking out the joint, such rapid rotation being knownas spinning and being accomplished either by rapid drive of apower-driven power tong or rapid rotation of the rotary table supportingthe length of pipe in the well bore, it is necessary during the finalstages of making up the pipe joint or during the initial stage ofbreaking out the pipe joint that the length of pipe disposed in the wellbore be tightly held as high torque is applied by the power pipe tongeither to finally make up the joint or initially break out the joint, asthe case may be. Accord ingly, it is the practice to employ a backuptong at least during the high torque stages of the operation of makingup and breaking out the pipe joints, and such backup tongs havevariously been conventional hand tongs secured to a post of the derrickby a cable, or backup tongs combined with the power tong which operateson the length of pipe supported in the derrick. It is desirable that thebackup tong be quickly engageable with and releasable from the length ofpipe disposed in the well bore so as to minimize loss of time and so asto eliminate the imposition of an axial force on the power driven tongand the backup tong, when such tongs are used in combination, whichaxial force is occasioned by the relative axial movement of the pipejoint as the threads are being rapidly relatively rotated during thespinning operation.

Summary Accordingly, an object of the present invention is to provide apipe gripping head applicable to backup tongs adapted to be employed incombination with a power 3,507,174 Patented Apr. 21, 1970 driven tong,in which the pipe-gripping means are adapted to be actuated intogripping engagement with the pipe as well as positively actuated out ofgripping engagement with the pipe.

Another object of the invention is to provide pipegriping means for abackup tong assembly, or the like, in which the pipe-gripping means arejaws actuatable into pipe-gripping engagement with the pipe in responseto rotation of a jaw carrying ring in either direction, the ring beingoperable by a pressure cylinder which is shiftable between a firstposition in which the cylinder will move the ring in one direction, anda second position at which the ring will move in the other direction.

Still another object of the invention is to provide a pipe tong assemblyin which a pipe engaging jaw carrying ring is supported on a framestructure for relative angular movement, the frame structure having acam ridge engageable by cam followers on the jaws, whereby the jaws willbe actuated positively between a pipe engagaing position and a retractedposition in response to rotation of said jaw carrying ring in eitherdirection, an actuator cylinder being selectively connectable to the jawcarrying ring at angularly spaced locations so as to effect movement ofsaid jaws between said positions to cause said jaws to grip a pipe jointpart to hold the same against rotation in either direction, whereby toenable the rotation of the other joint part in either direction toeither make up or break out pipe joints.

A further object is to provide a tong assembly, as aforesaid, whereinlatch means are provided for connecting the actuator cylinder to thespaced angular locations on the jaw carrying ring, said latch meansbeing automatically released upon actuation of means for shifting theactuator cylinder between the angularly spaced locations, so that thechanging of the direction of actuation of the jaw carrying ring may beeffected from a remote location.

Other objects and advantages of the invention will be hereinafterdescribed or will become apparent to those skilled in the art and thenovel features of the invention will be defined in the appended claims.

Brief description of the drawings FIG. 1 is a top plan view showing apower tong and backup tong assembly supported over a well bore;

FIG. 2 is a view in side elevation of the structure of FIG. 1;

FIG. 3 is an enlarged view, partly in top plan, with parts broken away,as taken on the line 33 of FIG. 2;

FIG. 4 is a fragmentary view in bottom plan showing the tong head of theinvention;

FIG. 5 is an enlarged view, partly in top plan and partly in horizontalsection, showing the tong head of the in vention;

FIG. 6 is a vertical sectional view on a reduced scale, as taken on theline -66 of FIG. 5;

FIG. 7 is a fragmentary view in vertical section and on a reduced scale,as taken on the line 7--7 of FIG. 5;

FIG. 8 is a fragmentary view in horizontal section, as taken on the line8--8 of FIG. 6;

FIG. 9 is a fragmentary view in vertical section, as taken on the line9-9 of FIG. 5;

FIG. 10 is a fragmentary view in vertical section, as taken on the line10--10 of FIG. 5; and

FIG. 11 is a schematic view illustrating the control system forelfecting selective actuation of the jaw carrying ring.

' Description of the preferred embodiment Referring first to FIGS. 1 and2, there is generally illustrated a tong assembly T adapted to besupported above the floor F of a drilling platform which may be part ofthe usual drilling rig mounted above a well bore and into which pipe,such as drill pipe or casing, is adapted to be run and from which suchpipe will be sometimes pulled, as in the case of drill pipe. Such a pipeis illustrated in FIGS. 1 and 2 as including an upper stand of pipe P1in the illustrative form of a stand of drill pipe having a tool jointpin end 1 thereon adapted to be threadedly connected by the tong T tothe box end 2 of a length or stand of the pipe P2 disposed in the wellbore. In order to support the tong assembly T in an operative positionabove the well bore so that the stand of pipe P1 may be loweredtherethrough for engagement with the pipe P2, a suitable crane C isprovided, including a boom 3 projecting from a vertically disposed post4. A cable 5 extends over sheaves 6, 6 and is connected to a pressureoperated cylinder mechanism 7 disposed within the post 4, whereby thetong assembly T may be raised and lowered relative to the post 4 andthereby relative to the well bore into which or from which pipe is beingremoved. Also forming a part of the crane C is a rabbet 8 slidablevertically along the post 4, there being a second cable 9 also connectedto the upper end of cylinder 7, extending over a sheave 10, andconnected also to the rabbet 8 so that the mass of the tong assembly maybe properly supported. This crane assembly may be of any desired type,but is preferably constructed as herein shown and in accordance with thedisclosure in the application for United States Letters Patent filedconcurrently herewith and entitled Power Tong Crane, Ser. No. 687,812.

The tong assembly, as is typical of tongs of the type here involved,includes a head section generally denoted at 11 and a supporting andpower transmission section generally denoted at 12. The latter sectionin the illustrative embodiment has a hydraulic motor 13 adapted to beconnected to a suitable source of motive fluid under pressure so as todrive the transmission mechanism .of the tong assembly, which may be ofany desired type, but which may preferably be constructed in accordancewith the disclosure in the application for United States Letters Patentfiled concurrently herewith and entitled Power Pipe Tong TransmissionAssembly, Ser. No. 687,815. The head section 11 of the tong assembly Tmay be of any desired type of tong head mechanism adapted to grip andeffect rotation of the pin end 1 of the pipe P1 while the box end 2 ofthe pipe P2 is held against rotation either in the usual rotary tableslips or by the backup tong assembly generally denoted at B, made inaccordance with the invention and hereinafter to be more fullydescribed. Thetong head 11 is preferably made in accordance with thedisclosure in the application for United States Letters Patent filedconcurrently herewith and entitled Pipe Tong Head, Ser. No. 687,830.

The backup tong assembly B, as bets illustrated in FIGS. 2 and 3,includes a support structure 201 comprising an elongated hollow case 202supported at its rear end 203 by a post 204 depending from the powertong assembly T. If desired, as will be appreciated by those skilled inthe art, the post 204 may extend through a chamber 205 so as to beengaged by a pressure foot 206 of a force sensing hydraulic device 207having a conduit 208 leading to a gauge which will show the angularforce applied to the backup tong B tending to cause angular movement ofthe support structure 201, as an indication of the make up torqueapplied to pipe joints held by the backup tong, as will hereinafter bedescribed, and rotated by the power tong assembly T.

At the forward end of the support structure 201 is a backup tong headassembly generally denoted at 209, the support structure 201 includingbrackets 210 connected to ears 211 formed as part of the head assembly209 by bolts 212. This head end of the backup tong assembly is also, inthe illustrative embodiment, supported beneath the power tong assembly Tby means of cars 213 projecting from the sides of the tong assembly Tand supporting bolts 214 which extend through outwardly extended gussets215 carried by the support structure 201, coiled springs 216 beingprovided between the gussets 215 and the ears 213 to cushion relativevertical movement between the head 11 of the power tong assembly T andthe head 209 of the backup tong assembly B.

The tong head assembly 209, as seen in FIGS. 5 to 9 includes a member217 which is in the form of a plate having an external marginalreinforcing flange 218 and an internal marginal flange 219, and the ears211 previously described, by which the tong head 209 is carried at thehead end of the support structure 201, being provided on the outerperipheral flange 218 of the plate member 217, so that the latterconstitutes what will be characterized herein as a stationary ring. Thisstationary ring 217 sup ports a relatively rotatable ring assemblygenerally denoted at 220. The ring assembly 220 comprises an upper plate221 and a lower plate 222 of generally triangular form, but truncated atthe apices so as to generally conform to the circular form of thestationary plate 217. At a suitable number of angularly spaced locationsthe plates 221 and 222 are provided with opposing internal bosses 223and 224 through which extend connecting bolts 225, and, at suchlocations, each of these plates may be further provided with axiallyextended arcuate flanges 226 and 227 which define therebetween radiallyopening windows 228 (see FIGS. 5 and 8).

The pipe gripping means comprise a plurality of jaws generally denotedat 230 which are adapted to be shifted through the windows 228 betweenretracted positions and inwardly projected positions at which the jaws230 will engage a pipe joint part, such as the joint part 2 of the pipeP2. These jaws 230 each comprise a generally U- shaped body having aninner vertical end wall 231 and upper and lower walls 232 and 233,respectively, these latter walls extending radially into overlying andunderlying relation to the stationary plate 217. The end wall 231 ofeach of the jaws 230 is, as best seen in FIGS. 5 and 7, provided withrecesses 234 and 235, respectively, adapted to receive complemental ears236 and 237 which project outwardly from the upper and lower ends of adie carrier 238, the latter having a vertically disposed slot 239adapted to receive a pipe engaging tong die 240 of suitableconstruction, the tong dies respectively being held in the slots 239 byfasteners 241. It will also be noted that the end walls 231 of the jaws230 are also provided with tong die slots 242 adapted to receive diessimilar to the dies 240, but that die carriers 238 of different radialprojection may be associated with the respective jaws 230 so as toenable the jaws to effectively engage pipe or pipe joints over a widerange of sizes, the illustrative die carrier 238 being adapted to engagean intermediate range of pipe sizes, while larger pipe sizes would beengaged by dies in the jaw slots 242 and the carriers 238 would beremoved. In order to releasa'bly secure the die carriers 238 on the endwalls 231 of the jaws 230, the ears 237 of the die carriers are providedwith openings adapted to accommodate locking screws 243 as seen in FIG.7.

When the jaws 230 are fully retracted, it will be noted that the endwalls 231 thereof would be radially outward from the inner periphery 244of the top plate 221 and the inner periphery 245 of the bottom plate 222of the rotatable ring assembly 220, but when a die carrier, such as thedie carrier 238, is provided on the jaws 230 the die carriers willproject radially inwardly relative to the peripheries 244 and 245 ofplates 22 1 and 222, respectively. Thus, guide means are provided withinthe inner peripheries of the plates 221 and 222, including an annularbody 246 having windows 247 adapted to register with the windows 228provided between the inner walls 226 and 227 of the plates 221 and 222.The guide body 246 has an inner periphery which projects inwardly beyondthe dies 240 in die carriers 238 so as to prevent engagement thereof bya pipe joint or pipe end. Beneath the guide body 246 is an outwardlyextended flange 248 adapted to be secured by fasteners 249 to the bottomplate 222 of the rotatable ring assembly 220. In order to substitute orremove the die carriers 238 from the jaws 230, as best illustrated inFIG. 4, the guide fasteners 249 must be removed to allow slight angularmovement of the guide relative to the ring assembly 220, whereby toexpose in guide flange notches 250 the fasteners 243 which secure thedie carriers 238 to the jaw walls 231, but when the guide is in fastenedposition, the flange 248 at least partially overlies holes 243a in thebottom plate 222 of the ring assembly 220 which are aligned with thefasteners 243 so as to preclude loss of these fasteners from theassembly during use.

Means are provided for effecting the retraction and radial projection ofthe jaws 230 to pipe engaging positions. Such means includes a cam ridge251 formed as at least the lower portion of the inner marginal flange219 of the stationary plate 217, and a roller 252 engaged with one sideof the ridge 251, as well as a roller 253, engaged with the other sideof the ridge 251. The roller 252, in the illustrative embodiment, is alarge roller disposed between the upper and lower walls 232 and 233 ofthe jaws 230 and rotatably supported on a shaft 254 extending betweenthe latter walls. The roller 253 in each jaw is a smaller rollerjournalled on a stud 255 extending upwardly through the lower wall 233of the jaw 230. As best seen in FIG. 5, the cam ridge 251 is acontinuous ridge having three similar segments, each cooperative withthe rollers 252 and 253 to effect movement of the respective jawsbetween the aforementioned retracted and inwardly projected positions.Each segment of the cam ridge 251 includes a central depression 251a anda pair of similar arcuately extended camming walls 251b and 2510extending arcuately from the central depression 251a. These walls 251])and 2510 respectively merge with the walls 251a and 251b of the adjacentcam ridge segments at points designated 2510?. In radial alignment withthe central depressions 251a, each of the cam ridge segments is providedwith an outwardly extended protuberance 251e, so that, as will be morefully understood hereinafter, the terminal stages of movement of the jawcarrying ring assembly 220 in a direction to cause retraction of thejaws will cause the rollers 252 to be seated in the central depressions251a between the respective camming surfaces or walls 251b and 251C. Inthis connection, it will now be apparent that angular movement of thering assembly 220 in either direction when the jaws 230 are in thepositions shown in FIG. 5 will result in said jaws being cammed by theaction of the rollers 252 on either cam wall 251]) or cam wall 2510 ofthe respective camming ridge segments inwardly towards a pipe locatedwithin the central opening of the tong head defined by the guide body246. *It will also be appreciated that re versal of the direction ofangular movement of the jaw carrying ring 220 will effect retraction ofthe jaws 230 by the action of the rollers 253 on the outer walls of therespective camming ridge segments.

Inasmuch as the jaws 230 will project more or less inwardly into thetong head opening, depending upon the size of the pipe joint disposedtherein, guide means are provided for the respective jaws, which guidemeans are adapted to cock slightly so as to maintain full facial contactwith the jaws when torque applied to the pipe tends to cause cocking ofthe jaws within the guide means for the jaws. This guide meanscomprises, in association with each of the jaws 230, upper and lowerguide pads 256 and 257, respectively, disposed in pad supports 258 and259, a pivot pin 260 pivotally mounting the respective pads 256 and apivot pin 261 pivotally mounting the respective pads 257 in theirsupports 258 and 259 for slight angular movement, these pads 256 and 257slidably engage the jaws 230 along their side walls and each of the pads256 and 257 may adjust angularly so as to maintain facial contact withthe jaws as the latter are caused to cock slightly angularly in responseto engagement with the pipe when the latter is subjected to angularforces.

Actuator means generally denoted at 265 are provided for effectingangular movement of the jaw carrying ring assembly 220, as aforesaid, inopposite jaw closing directions, from the fully retracted jaw positions,as well as for effecting angular movement of the ring assembly 220 inopposite jaw retracting directions. This actuator means 265 includes afluid pressure operated actuator cylinder 266 which is pivoted centrallyof the support structure 201 and in rearwardly spaced relation to thehead 209 on a pivot pin 267 supported in a bracket 268, as seen in FIG.3. Projecting from the actuator cylinder 266 is an actuator rod 269adapted to be connected to the ring assembly 220 at one location at oneside of a center line extending from pivot pin 267 through the center ofthe tong head in order to force the ring assembly 220 in one angular jawclosing direction, and alternately, to be connected to the ring assembly220 at the other side of said center line to cause angular movement ofthe ring assembly 220 in the other angular jaw closing direction,retraction of the rod causing reverse jaw opening angular movements ofthe ring assembly 220. As best seen in FIGS. 5 and 10, the rod 269 isconnected to a block 270. This block 270 has a head 271 which isdisposed between a pair of plates 272 and 273. Plate 272 is formed aspart of, or connected to, a mounting bracket 274 which is secured as byfasteners 275 to an upwardly extending reinforcing side wall 276extending along the margin of the lower plate 222 of the ring assembly220. The plate 273 likewise is formed as part of, or connected to, amounting bracket 277 which is secured as by fasteners 278 to thejust-mentioned side wall 276. Plate 272 has an elongated arcuate slot279, and plate 273 has a correspondingly elongated arcuate slot 280, inwhich vertical extensions of the head 271 of block 270 are disposed. Theopposite ends of the slots 279 and 280, as indicated at 281 and 282 inFIG. 5, constitute abutments engageable by the head 271 to limitmovement of said head relative to the plates 272 and 273. Means areprovided for shifting the head 271 between the limits provided by theslot ends 281 and 282, including a fluid pressure operated actuatorcylinder 283 pivotally supported at one end on a bracket 284, thecylinder 283 having a rod 285 connected by a pin-and-slot lost motionconnection 286 to a lever arm 287 projecting from the pivoted end of thering actuator cylinder 266. Accordingly, when rod 285 is retracted intocylinder 283, the actuator cylinder 266 will be caused to swing aboutits pivot 267 from the position shown in FIG. 3, at which the head 271is engaged with the abutment 282, to the other end of the slots intoengagement with the abutment 281. Conversely, when the actuator rod 285is projected from the cylinder 283, opposite pivotal movement of thering actuator cylinder 266 will occur. Thus, the actuator cylinder 283and its rod 285 constitute means for shifting the ring actuator cylinder266 to the above-mentioned opposite sides of the center line extendingbetween pivot pin 267 and the center of the tong head 209'. In addition,the lost motion connection 286 constitutes means enabling the ringactuator cylinder 266 to operate the move the ring assembly 220 ineither direction without interference from the connection of the rod 285to the lever arm 287, by which actuator cylinder 266 is caused to pivotbetween its two operative positions.

Means are provided for releasably latching the head 271 in itsrespective extreme positions. Accordingly, the head 271, as seen in FIG.10, is provided with a bore 288 in which is disposed a latch pin 289,the upper end of which is adapted to extend into a pin opening 290provided in a plate 291 mounted on the slotted plate 272 adjacent theabutment 281, when the head 271 is in that position. Adjacent theabutment 282 the latch pin 28? is adapted to engage in a pin opening 292in a plate 293 carried by the slotted plate 272. Means are provided forretracting the pin 289 from the pin openings 290 and 292 and, in theillustrative embodiment, the pin 289 is provided with a piston portion294 disposed in the bore 288; and the block 270 is provided with a fluidpassage 295 leading from a fluid conduit connector 296, whereby fluidunder pressure may be admitted to the bore 288 above the piston 294 toforce the pin 289 downwardly against the force of a spring 297 whichnormally biases the pin 289 into latching engagement with either of theplates 291 or 293 when the head 271 is in either of the positionsadjacent abutment 281 or 2 82.

Preferably, means are provided which may be controlled from a remotelocation, so that the latch pin 289 will be retracted when it is desiredto actuate the actuator cylinder 283 to shift the ring actuator cylinder266 between its two operative positions. Accordingly, as seen in FIG.ll, a control system is provided for supplying pressure to the pinretracting piston 294 when pressure is supplied to the actuator cylinder283 at either end of the latter.

Referring to FIG. 11, such a system is illustrated diagrammatically asincluding a conduit 300 leading from a source of fluid pressure at aremote location to a 4-way valve 301. This 4-way valve may be suitablyactuated as from a source of control fluid pressure to allow the flow ofhydraulic fluid to the latch from chamber 288 (FIG. through a conduit302 having therein a back flow preventing valve 303, another conduit 304also leading from the 4-Way valve 301 to the pin retracting chamber 288and having a back flow preventing valve 305 therein. A conduit 306interconnects the conduit 302 to one end of the actuator cylinder 283,and a conduit 307 connects the conduit 304 to the other end of theactuator cylinder 283, so that, under the control of the 4-way valve301, the actuating fluid pressure source conduit 300 may be selectivelyand simultaneously connected to one or the other ends of the bevelactuating cylinder 283 and to the latch pin retracting chamber 288.Normally, the latch pin chamber 288 communicates with an exhaust passage308 provided in the head 271 of block 270, and this passage 308communicates via a conduit 309 with a normally open exhaust valve 310.Accordingly, it is desired that when the latch pin is to be retractedthe exhaust valve 310 be closed. For this purpose there is illustrated aconduit 311 connected to the conduit 302 and leading to the exhaustvalve 310, and another conduit 312 is connected to the conduit 304 andleads to the exhaust valve 310, so that, upon the application ofpressure to the latch pin chamber 288 through either of the conduits 302or 304, the exhaust valve 310' is automatically closed; but when latchpin retracting pressure is relieved from conduits 302 or 304, theexhaust valve 310 will again automatically open so as to allow latch pinengaging spring 297 to force the latch pin to a latched position.

Also illustrated in FIG. 11 is a 4-way valve 313 adapted to effectopposite working of the double acting cylinder 266, whereby the ringassembly 220 is caused to be actuated in jaw closing and jaw openingdirections. Leading into the valve 313 from a suitable remote source offluid pressure is a conduit 314, and conduits respectively designated315 and 316 are selectively adapted to communicate with the sourceconduit 314 to cause operation of the cylinder 266 in oppositedirections, the other conduit 315 or 316 being connected to an exhaustconduit 317 leading back to the supply tank.

In the use of the tong assembly B described above in combination with apower tong assembly T, the latter will be operated to grip and rotate ajoint of pipe, in say a right-hand direction, when a pipe joint is to bemade up and during the initial stages of rotation of the pipe by thetong assembly T, the backup tong assembly B may remain idle. However,when the tool joints 1 and 2 shoulder, and the tong assembly B isemployed to apply high torque forces to the pipe P1, it is then desiredthat the backup tong B be operated to resist rotation of the pipe P2 ina right-hand direction. Under these circumstances, the ring actuatorcylinder 266 of the actuator means 265 should be in the angular positionshown in FIGS. 3 and 11, with the latch pin 2S9 connecting the actuatorrod 269 to the jaw carrying ring assembly 220 so as to effect right-handrotation of said ring assembly when pressure fluid is applied to thecylinder 266 to project the rod 269 therefrom. Such right-hand rotationof ring 220 will cause angular movement thereof relative to thestationary plate 217 and the cam ridge 251 formed on the latter, so thatthe jaw closing rollers 252 will progressively move along the cam walls251b, forcing the jaws 230 toward one another into gripping engagementwith the pipe joint 2. Thereafter, the tendency of the pipe P2 to rotateto the right with the pipe P1 will cause a corresponding tendency of thejaw carrying ring 220 to rotate to the right, thereby further energizingthe camming action of the tong assembly and forcing the jaws 230' intotighter gripping engagement with the pipe P2.

Conversely, when the power tong assembly T is being employed to breakout pipe joints by rotating the pipe P1 to the left, initial high torqueloads will be imposed on the pipe joint and the backup tong B should beengaged with the joint 2 to prevent left-hand rotation thereof. Underthese circumstances, the operator will effect release of the latch pin289 and will cause the application of fluid pressure to the actuatorcylinder 283 to retract rod 285, thereby shifting the ring actuatorcylinder 266 over-center into engagement with the abutment 281,whereupon the latch pin 289 may he re-engaged by the spring 297. Then,application of fluid pressure to the cylinder 266 will cause left-handrotation of the jaw carrying ring 220 which will cause movement of therollers 252 along cam surfaces 2510, thereby effecting closure of jaws230 on the pipe joint 2. Any tendency of the joint part 2 to rotate tothe left along with the pipe P1 will again effect self-energization ofthe backup tong, whereby the jaws will be more firmly forced intogripping engagement with the joint part 2.

Following either of the above described jaw engaging operations, thebackup tong jaws 230 will be positively retracted in response toretraction of the rod 269 in the ring actuator cylinder 266. In thisconnection, the ring assembly 220 will be pulled by rod 269 in the jawopening direction and the rollers 253 engaging the outer face of the camridge 251 will effect positive jaw retraction, these rollers, in theirfinal stage of movement, engaging the protuberances 251:: on the camridge 251 to seat the rollers 252 in the central depressions 251abetween cam ridges 25112 and 2510.

I claim:

1. Tong apparatus for making up and breaking out joints in Well pipe,said joints being composed of threaded pipe parts, a support structure,pipe engaging means carried by said support structure for relativeangular movement thereof, means for effecting such angular movement,said pipe engaging means including a ring, jaws carried by said ring andmovable between pipe engaging and retracted positions, means for movingsaid jaws between said positions in response to angular movement of saidring in opposite directions, said last-mentioned means comprising a camridge on said support structure, having inner and outer cam surfaces andcam follower means on said jaws engaged with said inner and outer camsurfaces of said cam ridge for camming said jaws to both of saidpositions upon angular movement of said ring in opposite directions.

2. Tong apparatus as defined in claim .1, wherein said cam ridgecomprises similar cam ridge segments engageable by said cam followers ofthe respective jaws upon movement of said ring in either direction forcamming said jaws toward a pipe gripping position.

3. Tong apparatus as defined in claim 1, wherein said support meanscomprises a central plate having said cam ridge thereon, said ringcomprising upper and lower plates rotatable relative to said centralplate, said jaws being carried between said upper and lower plates, and

said follower means includes rollers carried by said jaws and engagedwith opposite sides of the said cam ridge.

4. Tong apparatus as defined in claim 1, wherein said ring comprisesupper and lower plates, said jaws being slidably disposed between saidplates, said plates having means slidably guiding said jaws for radialmovement relative to said ring, including pivoted pads for allowing saidjaws to cock relative to said means slidably guiding said jaws.

5. Tong apparatus as defined in claim 1, wherein said pipe engagingmeans includes a ring, said means for effecting angular movement of saidpipe engaging means comprising an actuator cylinder carried by saidsupport structure and connected to said ring for moving the sameangularly in opposite directions, said actuator means being pivotallyconnected to said support structure and including means for shifting theconnection of said actuator means to said ring from one side of a centerline extending through said ring and said pivotal connection to theother side of said center line.

6. Tong apparatus as defined in claim 5, wherein said means for shiftingsaid actuator includes second actuator means and means providing a lostmotion connection interconnecting said second actuator means to saidfirstmentioned actuator means.

7. In tong apparatus for making up and breaking out joints of well pipe,a support structure, a stationary member carried by said supportstructure, a member movable rotatively relative to said stationarymember, jaws carried by said movable member, means for effectingmovement of said jaws between pipe gripping positions and retractedpositions responsive to rotation of said movable member between firstand second positions in either direction, operator means including apressure operated cylinder for actuating said movable member in oppositedirections, pivot means connecting said actuator cylinder to saidsupport structure at one end, and means for selectively connecting theother end of said actuator cylinder to said movable member at locationsat opposite sides of a center line extending from said pivot meansthrough the center of said movable member for selectively moving saidmovable member in either direction between said first and secondpositions.

8. Tong apparatus as defined in claim 7, wherein said operator meansincludes a second actuator cylinder connected to said first-mentionedactuator cylinder for moving the latter between positions at which saidother end of said first-mentioned actuator is connectable to saidmovable member at said positions.

9. Tong apparatus as defined in claim 8, wherein said first-mentionedactuator has a lever thereon and including lost motion means connectingsaid second actuator cylinder to said lever for allowing free movementof said lever when said movable member moves between said first andsecond positions.

10. Tong apparatus as defined in claim 7, wherein said means forselectively connecting said other end of said actuator cylinder to saidmovable member comprises a head carried by said actuator cylinder, alatch pin carried by said head, a pair of latch plates on said movablemember, guide means for guiding said latch head between said latchplates when said latch pin is disengaged from said latch plates, andincluding means for causing movement of said head along said guide meansbetween positions at which said latch pins are engageable with saidlatch plates.

11. Tong apparatus as defined in claim 7, wherein said means forselectively connecting said other end of said actuator cylinder to saidmovable member comprises a head carried by said actuator cylinder, alatch pin carried by said head, a pair of latch plates on said movablemember, guide means for guiding said latch head between said latchplates when said latch pin is disengaged from said latch plates,including means for causing move, ment of said head along said guidemeans between positions at which said latch pins are engageable withsaid latch plates, and means for retracting said latch pins from saidlatch plates at said positions.

12. Tong apparatus as defined in claim 10, wherein said means forcausing said movement of said head includes a fluid pressure operatedactuator, and said means for retracting said latch pins includes a fluidpressure operated actuator.

13. Tong apparatus as defined in claim 12, wherein means are providedfor applying fluid pressure to said actuator for said latch pin whenfluid pressure is supplied to said actuator for causing said movement ofsaid head.

References Cited UNITED STATES PATENTS 2,618,468 11/1952 Lundeen 81-572,737,839 3/1956 Paget 81-53 2,760,392 8/1956 Paget 81-53 2,846,909 8/1958 Mason 81-53 2,871,743 2/1959 Kelley 81-53 2,933,961 4/1960 Adams81-53 2,950,639 8/1960 Mason 81-53 3,180,186 4/ 1965 Catland 81-573,261,241 7/1966 Catland 81-57 3,380,323 4/ 1968 Campbell 81-54 JAMES L.JONES, 111., Primary Examiner 'U.S. Cl. X.R. 81-57.21

